Let me introduce you to a new word and a fascinating dual purpose for it. The word is “CAPTCHA.” It stands for “Completely Automated Public Turning test to tell Computers and Humans Apart.” It is one of those squiggly words that you have to retype when you buy things online. I have become rather proficient at this test since I have to engage in it every time I purchase baseball tickets online.

These squiggly words actually serve an important purpose. Only humans can decipher them. That protects websites from hackers. It also prevents unwanted Internet bots from accessing websites. A normal human can usually read a CAPTCHA. The most sophisticated Internet bot cannot process these image letters.

But this is not the end of the story, but actually the beginning of an idea that is serving libraries around the world. Luis von Ahn who helped invent CAPTCHA felt guilty about the time wasted by the estimated 200 million CAPTCHAs being typed byhumans around the world every day. There is really no way to speed up the process, so why not use it for something productive?

Why not use humans to decipher words from ancient texts that have not been digitzed because the computer scanners have difficulty reading the handwriting. Computers cannot recognize nearly a third of the words printed in the millions of booksthat  are more than 50 years old.

His solution, therefore, was to add a second squiggly word (called a reCAPTCHA) that was taken from one of these ancient texts. While typing in the CAPTCHA, you are proving you are human. When you type in the reCAPTCHA, you are adding to the sum of the world’s knowledge.

About 350,000 websites have adopted reCAPTCHA. That means that more than 100 million words are being deciphered every day. That works out to about 2.5 million books a year that are being digitized because of our efforts. I don’t know about you, but now I feel much better about taking the time to decipher a CAPTCHA.